This is a hollow region which contains the spinal cord and the nerve roots of the Cauda equina. The vertebral bodies and discs form the anterior boundary of the Spinal canal (with the posterior longitudinal ligament (PLL)) in between. The segments of bone lateral and on either side of the Spinal canal are the pedicles. The pedicles connect the vertebral bodies to the posterior elements (Facet joints, Laminae and the Spinous processes). Hypertrophic changes to the Facet joints and ligamentum flavum (Yellow ligament) may result in Spinal canal stenosis (or narrowing) with compression of the spinal cord or nerve roots.